JSP分页demo

最新推荐文章于 2025-06-05 00:21:06 发布

ucdream

最新推荐文章于 2025-06-05 00:21:06 发布

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CC 4.0 BY-SA版权

文章标签： JSP CSS 正则表达式 Cache JavaScript ViewUI

本文链接：https://blog.youkuaiyun.com/chennanfei/article/details/83555596

首先创建一个类PagingDemo提供测试数据，方法getResults获得请求的数据，prepareURL产生每一个page的url。prepareURL方法有点笨，用正则表达式也可以完成，不过我不知道如何写

package test.demo;

import java.util.ArrayList;
import java.util.List;

import javax.servlet.http.HttpServletRequest;

public class PagingDemo {
	private static final List testRepo = new ArrayList();
	private int totalCount;

	static {
		for (int i = 0; i < 100; i++) {
			testRepo.add("testdata." + i);
		}
	}

	public static void main(String[] args) {

	}

	public int getTotalCount() {
		return this.totalCount;
	}

	public List getResults(int page, int count) {
		if (page < 1 || count < 1) {
			return null;
		}
		totalCount = testRepo.size();
		int firstIndex = (page - 1) * count;
		if (firstIndex >= totalCount) {
			return null;
		}
		int lastIndex = firstIndex + count;
		if (lastIndex > totalCount) {
			lastIndex = totalCount;
		}
		return testRepo.subList(firstIndex, lastIndex);
	}

	public static String prepareURL(HttpServletRequest request) {
		String requestUrl = request.getRequestURI() + "?";
		String queryString = request.getQueryString();
		if (queryString != null) {
			// remove the parameter 'page' from the query string
			int index = queryString.indexOf("page=");
			if (index != -1) {
				int i = index;
				for (; i < queryString.length(); i++) {
					char ch = queryString.charAt(i);
					if (ch == '&') {
						i++;
						break;
					}
				}

				String sub = queryString.substring(index, i);
				requestUrl += queryString.replace(sub, "")
						+ (i < queryString.length() ? "&page=" : "page=");
			}
		}
		else {
			requestUrl += "page=";
		}
		return requestUrl;
	}
}

页面代码：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@page import="test.demo.PagingDemo"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";

String requestUrl = PagingDemo.prepareURL(request);
String pageNum = request.getParameter("page");
if(pageNum == null) {
	pageNum = "1";
}
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>pages</title>
    
	<meta http-equiv="pragma" content="no-cache">
	<meta http-equiv="cache-control" content="no-cache">
	<meta http-equiv="expires" content="0">    
	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
	<meta http-equiv="description" content="This is my page">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->
	<style type="text/css">
		ul {margin:0px;padding:0px;}
		ul li {list-style-type: none;}
		a:link, a:visited {color:gray;text-decoration:none;padding:2px 5px;}
		.paging li {float:left;border:1px solid gray;text-align:center;margin:2px;color:gray;}
	</style>

  </head>
  
  <body>
  	<div style="width:400px;height:300px;border:1px solid blue;">
  		<ul>
	  	<%
	  		int pn = 1;
	  		try {
	  			pn = Integer.valueOf(pageNum);
	  			if(pn < 1) {
	  				pn = 1;
	  			}
	  		}
	  		catch (Exception e) {
	  			pn = 1;
	  		}
	  		int maxResultCount = 15;
	  		PagingDemo demo = new PagingDemo();
	  		List results = demo.getResults(pn, maxResultCount);
	  		if(results == null || results.isEmpty()) {
	  			out.println("<li>No results need to be shown</li>");
	  		}
	  		else {
		  		for(int i = 0; i < results.size(); i++) {
		  			out.println("<li>" + results.get(i) + "</li>");	  			
		  		}
		  		
		  		int total = demo.getTotalCount();
		  		int totalPages = total / maxResultCount;
		  		if(total % maxResultCount != 0) {
		  			totalPages++;
		  		}
		  		
		  		if(totalPages > 1) {
			  		int firstPage = pn - 2;
			  		int lastPage = pn + 2;
			  		if(firstPage < 1) {
			  			firstPage = 1;
			  		}
			  		if(lastPage > totalPages) {
			  			lastPage = totalPages;
			  		}
			  		out.println("<div class='paging'><ul>");
			  		out.println("<li>" + pn + "/" + totalPages + "</li>");
			  		if(pn > 1) {
			  			out.println("<li><a href='"+ requestUrl + (pn - 1) +"'>&lt;&lt;</a></li>");
			  		}
			  		for(int i = firstPage; i <= lastPage; i++) {
			  			if(i != pn) {
			  				out.println("<li><a href='"+ requestUrl + i + "'>" + i +"</a></li>");
			  			}
			  			else {
			  				out.println("<li><a style='color:white;background:gray;' href='"+ requestUrl + i + "'>" + i +"</a></li>");
			  			}
			  		}
			  		if(pn < totalPages) {
			  			out.println("<li><a href='"+ requestUrl + (pn + 1) +"'>&gt;&gt;</a></li>");
			  		}
			  		out.println("</ul></div>");
		  		}
	  		}
  		%>
  		</ul>
  	</div>
  	
    
    <script type="text/javascript">
    	function removeParamFromUrl(url, param){
    		if(url === null || url.indexOf("http:") != 0 || typeof param === "undefined" || param === null) {
    			return null;
    		}
    		index = url.indexOf(param + "=");
    		if(index === -1) {
    			return null;
    		}
    		replacedStr = null;
    		lastChar = url.charAt(index - 1);
    		if(lastChar === "&" || lastChar === "?"){
	    		for (i = index; i < url.length; i += 1) {
	    			if(url[i] === "&") {
	    				replacedStr = url.substring(index, i + 1);
	    				break;
	    			}
	    		}
	    		if(i === url.length) {
	    			replacedStr = url.substring(index - 1);
	    		} 
    		}  
    		
    		if(replacedStr !== null) {
    			url = url.replace(replacedStr, "");
    		}
    		return url;
    	}
    	
    	PagingBar = function(total, pages, page){
    		
    	}
    </script>
  </body>
</html>

一个简单的分页就完成了